In order to fabricate advanced integrated circuits cost-effectively, manufacturing defect densities need to be driven as low as possible and device and process controls need to be adjusted to drive device and circuit parametrics and performances to within specified ranges. One method of doing so is to place defect and performance monitor structures, as well as test circuits in the scribe line. A scribe line is an area between integrated circuits fabricated in arrays on wafers where dicing will occur. The scribe line contains no circuit elements required for the normal functioning of the integrated circuit. Scribe lines are also known as streets or kerfs. Scribe lines are where the cuts to separate a wafer (which contains many chips) into individual chips are made. However, not only do the monitor structures that are most desirable consume large areas of the scribe line, but additionally the area of the scribe line is limited and continues to shrink as productivity demands increase, with the result being that all desirable monitors will not fit in the available scribe line area.
Therefore, there is a continuing need for placing more monitor structures on integrated circuits than is currently possible.